U.S. patent number 6,478,399 [Application Number 09/562,471] was granted by the patent office on 2002-11-12 for printer and print head unit for same.
This patent grant is currently assigned to Seiko Epson Corporation. Invention is credited to Munehide Kanaya, Toyohiko Mitsuzawa.
United States Patent |
6,478,399 |
Mitsuzawa , et al. |
November 12, 2002 |
Printer and print head unit for same
Abstract
A print head unit is provided with preset head identification
information that is based on variations in print head unit
characteristics arising in the course of manufacturing the print
head unit. The printer executes printing processing in accordance
with printing processing parameters that are determined on the
basis of the head identification information.
Inventors: |
Mitsuzawa; Toyohiko
(Nagano-ken, JP), Kanaya; Munehide (Nagano-ken,
JP) |
Assignee: |
Seiko Epson Corporation (Tokyo,
JP)
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Family
ID: |
26544772 |
Appl.
No.: |
09/562,471 |
Filed: |
May 1, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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PCTJP9904689 |
Aug 30, 1999 |
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Foreign Application Priority Data
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Aug 31, 1998 [JP] |
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10-260837 |
Aug 31, 1998 [JP] |
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10-260838 |
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Current U.S.
Class: |
347/19 |
Current CPC
Class: |
B41J
2/17546 (20130101); B41J 2/17566 (20130101); B41J
2202/17 (20130101) |
Current International
Class: |
B41J
2/045 (20060101); B41J 2/175 (20060101); B41J
002/01 () |
Field of
Search: |
;347/19,15,37
;400/74 |
References Cited
[Referenced By]
U.S. Patent Documents
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4741634 |
May 1988 |
Nozaki et al. |
4872027 |
October 1989 |
Buskirk et al. |
5049898 |
September 1991 |
Arthur et al. |
5363134 |
November 1994 |
Barbehenn et al. |
5699091 |
December 1997 |
Bullock et al. |
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Foreign Patent Documents
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2-167755 |
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Jun 1990 |
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JP |
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9-314828 |
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Dec 1997 |
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JP |
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WO 98/45119 |
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Oct 1998 |
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WO |
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Primary Examiner: Hallacher; Craig
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier
& Neustadt, P.C.
Parent Case Text
This is a continuation of application Ser. No. PCT/JP99/04689,
filed Aug. 30, 1999.
Claims
What is claimed is:
1. A printing apparatus that prints using a print head unit
comprising a print head having a plurality of nozzles for ejecting
ink droplets, wherein the print head unit is provided with readable
head identification information that is predetermined based on
variations in print head unit characteristics caused by fabrication
error of the print head unit, and the printing apparatus comprises:
a control section that executes printing process in accordance with
printing process parameters determined according to the head
identification information; a print mode memory for storing a
plurality of dot printing modes each selectively applicable to the
print head unit, the plurality of dot printing modes having
substantially the same printing speeds at substantially the same
printing resolution, the dot printing mode defining a scanning
method used during printing effected by forming dots; and wherein
the head identification information further includes printing mode
information for specifying a preferable dot printing mode from
among the plurality of dot printing modes, the preferable dot
printing mode being selected according to the print head unit
characteristics.
2. A printing apparatus according to claim 1, wherein the head
identification information is stored in a non-volatile memory
provided on the print head unit.
3. A printing apparatus according to claim 2, wherein the print
head unit comprises the non-volatile memory having a memory area
storing print head unit service history information.
4. A printing apparatus according to claim 1, wherein the head
identification information is displayed on a surface of the print
head unit.
5. A printing apparatus according to claim 1, further comprising a
plurality of the print head units; and wherein the head
identification information is readably provided on each print head
unit.
6. A printing apparatus according to claim 1, comprising: means for
writing print head unit service history information into the
non-volatile memory.
7. A print head unit for use in a printing apparatus having a print
mode memory for storing a plurality of dot printing modes each
selectively applicable to the print head unit, the plurality of dot
printing modes having substantially the same printing speeds at
substantially the same printing resolution, the dot printing mode
defining a scanning method used during printing effected by forming
dots, wherein the print head unit is provided with readable head
identification information that is predetermined based on
variations in print head unit characteristics caused by fabrication
error of the print head unit, the head identification information
including printing mode information for specifying a preferable dot
printing mode from among the plurality of dot printing modes, the
preferable dot printing mode being selected according to the print
head unit characteristics.
8. A print head according to claim 7, comprising a non-volatile
memory having a memory area storing print head unit service history
information.
9. A print head unit according to claim 7, wherein the head
identification information is displayed on a surface of the print
head unit.
10. A printing apparatus that prints dots on a print medium,
comprising: a print head that includes a plurality of dot formation
elements for forming dots on the print medium; a main scanning
drive section that at least relatively moves the print head and the
print medium for main scanning; a head drive section that drives at
least a portion of the plurality of dot formation elements to form
dots during main scanning; a sub-scanning drive section that at
least relatively moves the print head and the print medium for
sub-scanning; and a control section for controlling printing,
wherein the control section includes: a printing mode storage
section for storing a plurality of dot printing modes each defining
the main and sub-scanning operations for printing dots and each
being selectively applicable to the print head, and a mode
selection information setting section for specifying a preferable
printing mode from among the plurality of dot printing modes, the
preferable printing mode being determined based on variations in
print head characteristics caused by fabrication error of the print
head, wherein the control section executes printing according to
the dot printing mode specified by the mode selection information;
and wherein the printing modes with respect to at least one print
resolution are divided into a plurality of printing mode groups
having mutually different printing speeds, and the plurality of
printing mode groups pertaining to said at least one print
resolution are arranged so that the number of dot printing modes
included in a group increases as its printing speed decreases.
11. A printing apparatus according to claim 10, wherein the mode
selection information setting section has mode selection data that
specifies a dot printing mode for each printing mode group having a
different combination of print resolution and printing speed.
12. A method of operating a print head unit, comprising: storing a
plurality of dot printing modes each selectively applicable to the
print head unit, the plurality of dot printing modes having
substantially the same printing speeds at substantially the same
printing resolution, the dot printing mode defining a scanning
method used during printing effected by forming dots; providing
readable head information on the print head unit that is
predetermined based on variations in print head unit
characteristics caused by fabrication error of the print head unit,
the information including printing mode information for specifying
a preferable dot printing mode from among the plurality of dot
printing modes, the preferable dot printing mode being selected
according to the print head unit characteristics; reading the
information; and executing printing in accordance with the head
identification information.
13. A method according to claim 12, comprising: providing the
information for each of a plurality of print heads; executing
printing for each of the print heads according to the respective
information.
14. A printing apparatus that prints using a print head unit,
wherein the print head unit is provided with readable head
identification information that is predetermined based on
variations in print head unit characteristics arising during
manufacture of the print head unit, the printing apparatus
comprises a print mode memory for storing a plurality of dot
printing modes each selectively applicable to the print head unit,
the dot printing mode defining a scanning method used during
printing effected by forming dots, and a control section that
executes printing process in accordance with printing process
parameters determined according to the head identification
information and said dot printing modes.
15. A print head unit for use in a printing apparatus having a
print mode memory for storing a plurality of dot printing modes
each selectively applicable to the print head unit, the plurality
of dot printing modes having substantially the same printing speeds
at substantially the same printing resolution, the dot printing
mode defining a scanning method used during printing effected by
forming dots, wherein the print head unit is provided with readable
head identification information that is predetermined based on
variations in print head unit characteristics arising during
manufacture of the print head unit and printing mode information
for specifying a preferred printing mode, the head identification
information including printing mode information for specifying a
preferable dot printing mode from among the plurality of dot
printing modes, the preferable dot printing mode being selected
according to the print head unit characteristics.
Description
FIELD OF THE INVENTION
The present invention relates to a printer, and to a print head
unit for use with the printer.
BACKGROUND ART
Normally printers are provided with a print head unit to effect the
printing. In order to obtain good quality printing it is preferable
for the various printing processing parameters, such as the head
drive voltage, for example, to be adjusted to match the
characteristics of the print head unit.
However, print head unit characteristics vary according to the
manufacturing history of the print head unit concerned. Thus, to
achieve good quality printing with each printer, there has been a
need for a technology that enables such good quality printing to be
attained by setting printing processing parameters that are
appropriate to the characteristics of the print head unit used with
each individual printer.
Accordingly, an object of the present invention is to provide a
technology that enables good quality printing to be attained in
accordance with the individual characteristics of each printer.
SUMMARY OF THE INVENTION
To attain at least part of the above objects, the print head unit
according to the present invention is provided with head
identification information in a readable form that is predetermined
based on the variations in print head unit characteristics arising
in the course of manufacturing the print head unit. The printer
executes printing processing in accordance with the printing
processing parameters determined on the basis of the head
identification information.
Here, "print head unit" denotes a print head that is detachably
attached to a printer as one unit. The printer can set appropriate
printing processing parameters based on the head identification
information with which the print head unit is equipped in a
readable form, and executes the printing processing in accordance
with the parameters thus set. As such, good quality can be
performed in line with the characteristics of the print head unit
used on each printer.
The head identification information may be stored in a non-volatile
memory provided on the print head unit. Such an arrangement allows
the printing processing parameters to be readily set by reading out
the head identification information from the non-volatile
memory.
It may also be arranged so that the service history of the print
head unit can be written to the non-volatile memory. This allows
the service life of the print head unit to be judged based on the
service history.
The head identification information may be displayed on the surface
of the print head unit.
The above printer may be provided with a print mode memory for
storing a plurality of dot printing modes that have substantially
equal printing speeds at the same resolution, where the dot
printing mode defines the scanning method used during printing
effected by forming dots, and the head identification information
may also include printing mode information for specifying a
preferable dot printing mode from among the plurality of dot
printing modes.
Such an arrangement makes it possible to readily select a dot
printing mode, based on the print head unit characteristics, that
enables good quality printing to be effected.
With respect to printers having a plurality of print head units,
each print head unit may be provided with the head identification
information in a readable form. Such an arrangement enables the
preferred printing processing parameters to be set that are based
on the individual characteristics of each of the print head
units.
The above plurality of dot printing modes can be arranged so that
with respect to at least one print resolution, the printing modes
are divided into a plurality of printing mode groups having
mutually different printing speeds, wherein the plurality of
printing mode groups pertaining to said at least one print
resolution are arranged so that the number of dot printing modes
included in a group increases as its printing speed decreases.
With respect to each individual such printer, a preferable dot
printing mode to achieve high quality may be selected from the
plurality of dot printing modes stored in the print mode memory,
and mode selection information indicating the preferable dot
printing mode can be set beforehand in a mode selection information
setting section. This makes it possible to use a preferable dot
printing mode that is best suited for each printer. When printing
is performed at the same resolution at a relatively lower printing
speed, the difference in quality between dot printing modes tends
to become greater. However, since the printer described above is
provided with a dot printing mode in which, with respect to at
least one print resolution, the slower the printing speed becomes,
the larger number of the dot recording modes are provided, high
quality printing can be more easily achieved at relatively low
printing speeds.
The mode selection information setting section may have mode
selection data that specifies one dot printing mode for each
printing mode groups having a different combination of print
resolution and printing speed.
Such an arrangement allows a preferable dot printing mode to be
specified independently for each of the plurality of printing mode
groups, thereby enabling high print quality to be readily obtained
with each printing mode group.
The invention can be realized in various forms such as a printer, a
printing method, a print head unit and so forth.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of the general configuration of the image
processing system of the invention.
FIG. 2 shows the general configuration of a printer 20 according to
an embodiment of the invention.
FIG. 3 is a block diagram showing the configuration of the control
circuit 40 of the printer 20.
FIG. 4 is a perspective view of the print head unit 60.
FIG. 5 shows the ink emission structure of the print heads.
FIGS. 6(A) and 6(B) show how ink particles Ip are emitted by the
expansion of a piezoelectric element PE.
FIG. 7 shows the positional correspondence between the rows of
nozzles in the print head 28 and the actuator circuits.
FIG. 8 shows the positional correspondence between the rows of
nozzles in the print head 28 and the actuator circuits.
FIGS. 9(a)-9(e) show the contents of the head identification
information displayed on a head ID seal 100.
FIG. 10 shows a drive signal waveform for fixed dot quantity
printing.
FIG. 11 shows an example of fixed dot quantity printing.
FIG. 12 shows a drive signal waveform for variable dot quantity
printing.
FIG. 13 shows an example of variable dot quantity printing.
FIGS. 14(A) and 14(B) illustrate parameters prescribing the dot
printing mode.
FIGS. 15(A)-15(D) show the scanning parameters used for printing in
each of four dot printing modes at substantially the same printing
speed.
FIG. 16 is a flow chart of the steps of installing print head unit
60 on the printer 20.
FIG. 17 shows a print head 28a of a print head unit in a second
embodiment of the invention.
FIG. 18 shows an example of the relationship between print head
units and control circuit in a printer equipped with multiple print
head units.
FIG. 19 is a function block diagram of the arrangement used to
effect drive control for each dot printing mode, in a third
embodiment.
FIGS. 20(A)-20(C) show the scanning parameters used in the third
embodiment for printing in each of four dot printing modes at
substantially the same printing speed.
FIGS. 21(A) and 21(B) show the contents of the printing mode table
and mode ID memory used in the third embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A. Configuration of Apparatus
FIG. 1 is a block diagram showing the configuration of a color
image processing system that is an embodiment of the present
invention. The color image processing system has a scanner 320, a
personal computer 300 and a color printer 20. The personal computer
300 has a color display 330. The scanner 320 reads color image data
from a color original and supplies to the personal computer 300
basic color image data ORG comprised of three color components red
(R), green (G) and blue (B).
The personal computer 300 contains components (not shown) such as
CPU, RAM and ROM and runs an application program 305 under a
prescribed operating system. The operating system incorporates a
video driver 301 and a printer driver 306. By means of these
drivers, the application program 305 outputs final color image data
FNL. The application program 305, which is used to retouch images
and so forth, subjects the image from the scanner to prescribed
processing while using the video driver 301 to display the image on
a CRT display 330. When the application program 305 issues an
instruction to print, the printer driver 306 receives the image
information from the application program 305 and converts the image
information to signals (in this case, binarized signals for each of
the colors cyan (C), magenta (M), yellow (Y) and black (K)) that
enable the printer 20 to print the image. In the example of FIG. 1,
the printer driver 306 includes a rasterizer 307 that converts the
color image data handled by the application program 305 to dot unit
image data, a color correction module 308 that performs color
correction of the dot unit image data in accordance with the cyan,
magenta and yellow inks used by the printer 20, a color correction
table CT used by the color correction module 308, a halftone module
309 that generates, from the color corrected image information,
halftone image information expressing a density for a given area in
accordance with the presence or absence of ink on each dot, and a
mode selection information writing module 310 for writing the mode
selection information described below into a memory in the printer
20.
FIG. 2 shows the general configuration of the printer 20. The
printer 20 includes a mechanism driven by a paper feed motor 22 to
transport paper P, a mechanism driven by a carriage motor 24 to
effect reciprocating movement of a carriage 30 axially along a
platen 26, a mechanism for driving a print head unit 60 (also
referred to as a print head assembly) mounted on the carriage 30 to
control ink emission and dot formation, and a control circuit 40
that controls signals moving between a control panel 32 and the
feed motor 22, the carriage motor 24 and the print head unit 60.
The control circuit 40 is connected to a computer 88 via a
connector 56.
The paper transport mechanism includes a gear-train (not shown)
that transmits the rotation of the feed motor 22 to the platen 26
and to paper transport rollers (not shown). The mechanism for
reciprocating the carriage 30 includes a slide-shaft 34 that
slidably supports the carriage 30 and is disposed parallel to the
axis of the platen 26, a pulley 38 connected to the carriage motor
24 by an endless drive belt 36, and a position sensor 39 for
detecting the starting position of the carriage 30.
FIG. 3 shows the configuration of the control circuit 40 comprising
the heart of the printer 20. The control circuit 40 is configured
as an arithmetical logic processing circuit that includes a CPU 41,
a programmable ROM (PROM) 43, RAM 44 and a character generator (CG)
45 in which is stored a character dot matrix. The control circuit
40 is also provided with an interface (I/F) circuit 50 for
interfacing with an external motor and the like, a head drive
circuit 52 that is connected to the I/F circuit 50 and drives the
print head unit 60, and a motor drive circuit 54 that drives the
feed motor 22 and the carriage motor 24. The I/F circuit 50
incorporates a parallel interface circuit and can receive print
signals PS from the computer 300 via the connector 56.
The specific configuration of the print head unit 60 and the
working principle by which ink is emitted will be described. As
shown in FIG. 4, the print head unit 60 is an L-shaped unit able to
hold black and color ink cartridges (not shown). The print head
unit 60 is provided with a divider plate 31 that allows both
cartridges to be installed.
An ID seal 100 is provided on the top edge of the print head unit
60. The ID seal 100 displays head identification information
relating to the print head unit 60. Details of the information
provided by the ID seal 100 are described later.
The bottom part of the print head unit 60 is provided with ink
channels 71-76 via which ink is supplied from ink tanks to the
print head 28 (described below). When black and color ink
cartridges are installed by being pressed down into the print head
unit 60, the ink channels 71-76 are inserted into the respective
cartridges.
The ink emission mechanism will now be briefly explained. When an
ink cartridge is installed on the print head unit 60, ink from the
cartridge is drawn out via the ink channels 71-76 and channeled to
the print head 28 provided on the underside of the print head unit
60, as shown in FIG. 5.
The print head 28 has a plurality of nozzles n arranged in a line
for each color, a piezoelectric element PE provided for each nozzle
n, and an actuator circuit 90 for operating the piezoelectric
element PE in accordance with drive signals from the head drive
circuit 52 (FIG. 3). The head drive circuit 52 generates a common
drive signal applied in common to all nozzles and transmits the
signals to the print head 28. In accordance with a print signal PS
supplied from the computer 88 for each nozzle, the actuator circuit
90 is latched on (ink is emitted) or off (ink is not emitted), and
applies a drive signal to piezoelectric elements PE only in respect
of nozzles that are switched on. Applying an electric charge to a
piezoelectric element creates stress in the crystalline structure,
which is used to obtain high-speed conversion of electrical to
mechanical energy. The term "actuator" is used to refer
collectively to the piezoelectric element PE and the actuator
circuit 90.
FIGS. 6(A) and 6(B) show structural details of the piezoelectric
element PE and a nozzle n. The piezoelectric element PE is provided
in contact with an ink passage 80 through which ink flows to the
nozzle n. In this embodiment, when a voltage of prescribed duration
is applied across the electrodes of the piezoelectric element PE,
the piezoelectric element PE rapidly expands, deforming a wall of
the ink channel 80, as shown in FIG. 6(B). This reduces the volume
of the ink channel 80 by an amount corresponding to the expansion
of the piezoelectric element PE, thereby expelling a corresponding
amount of ink in the form of an ink particle Ip that is emitted at
a high speed from the nozzle n. Printing is effected by these ink
particles Ip impacting the paper P on the platen 26.
FIGS. 7 and 8 show the positional relationship between the rows of
nozzles and the actuator sets in the print head 28. This printer 20
prints using ink of the four colors black (K), cyan (C), magenta
(M) and yellow (Y). To increase the speed of monochrome printing,
there are three rows of nozzles for black ink. For each of the
other three colors, there is one row of nozzles. The actuator
circuit 90 comprises a first actuator chip 91 for emitting ink from
two black ink nozzles, a second actuator chip 92 for emitting ink
from a row of black ink nozzles and a row of cyan ink nozzles, and
a third actuator chip 93 for emitting ink from a row of magenta ink
nozzles and a row of yellow ink nozzles. Monochrome printing is
effected using just the two rows of black ink nozzles of the first
actuator chip 91. During color printing, the nozzles of all three
actuator chips are used to effect printing in the four colors.
The reason why the component 60 shown in FIG. 4 comprising the
print head 28 and the ink cartridge holders is called "print head
unit" is because it is removably installed in the inkjet printer 20
as a single component. Thus, when a print head 28 is to be
replaced, it is the print head unit 60 itself that is replaced.
The PROM 43 in the control circuit 40 (FIG. 3) contains dot
printing mode information that includes the parameters for a
plurality of dot printing modes. Here, "dot printing mode" means a
mode for printing dots prescribed by the number of nozzles in a row
that are actually used, the subscanning feed amount, and so forth.
Herein, "printing method," "printing mode" and "print mode" are
used substantially interchangeably. Specific examples of dot
printing modes and the related parameters are described later. Mode
selection information for selection of a preferable mode from among
the plurality of dot printing modes is also stored in the PROM
43.
Also as explained later herein, the dot printing modes are divided
into a plurality of printing mode groups by print resolution and
printing speed, with each of the printing mode groups including at
least one dot printing mode. In each printing mode group, a mode
that enables the highest quality images to be printed is selected
as a preferable dot printing mode. The quality of the images
printed in each dot printing mode depends on the alignment
characteristics of the nozzles in the print head 28 (the actual
position of each nozzle). For example, there are cases in which
there are two nozzles in an array that deviate from the design
position away from each other (or towards each other). When the two
nozzles are used to print two adjacent raster lines, "banding" or a
streak of degraded image portion is produced between the raster
lines. The combination of nozzles to be used to form adjacent
raster lines is determined in accordance with the dot printing mode
(especially the sub-scanning feed amount). Consequently, what is
the preferable dot printing mode depends on the characteristics of
the print head 28 (the actual position of each nozzle) used in the
printer. Since the dot printing mode specified by the mode
selection information is determined by the characteristics of the
print head 28, the mode selection information can be thought of as
an identifier denoting the type of print head 28. Thus, herein the
mode selection information is, also referred to as "head ID" or
"mode ID."
When the printer driver 306 is installed during boot-up of the
computer 300, the dot printing mode information is retrieved from
the PROM 43 by the printer driver 306. Thus, the dot printing mode
information relating to the preferable dot printing mode specified
by the mode selection information is read in from the PROM 43 by
the printer driver 306. Processing by the rasterizer 307 and
halftone module 309 and main and sub scanning operations are
executed on the basis of this dot printing mode information.
The PROM 43 may be formed using any non-volatile rewritable memory,
such as for example EEPROM or flash memory. While it is preferable
for the mode selection information to be stored in a rewritable
non-volatile memory, it can be stored in a ROM. Similarly, the
plurality of dot printing mode information may be stored in a
storage means other than PROM 43, or may be registered in the
printer driver 306.
B. First Embodiment
In the first embodiment of the invention described below, a head ID
seal 100 (FIG. 4) that has been adhered beforehand to the-print
head unit 60 is used to set the preferable dot printing mode.
FIG. 9. shows details of the head identification information
displayed on the head ID seal 100. A barcode 102 and ID symbols 104
are printed on the head ID seal 100. The eight symbols S, 2, Q, Y,
L, J, 1, N are the prescribed ID symbols 104. The barcode 102
represents the same eight ID symbols. From the upper left, the
eight symbols denote: first drive voltage information VH1, actuator
rank information AR, second drive voltage information VH2, third
drive voltage information VH3, first ink emission amount
information IW1, second ink emission amount information IW2, and
checksum data CID. Checksum data CID is used to check whether there
is error in the other seven information items.
The drive voltages VH1-VH3 and the actuator rank information AR are
associated with the waveform of the common drive signal generated
by the head drive circuit 52. The printer 20 of this embodiment can
perform fixed dot quantity printing using dots of a fixed size, and
variable dot quantity printing using dots of three sizes. The
waveform of the common drive signal used during fixed dot quantity
printing is not the same as the waveform of the common drive signal
used during variable dot quantity printing. First, the common drive
signal waveform will be explained.
FIG. 10 is a common drive signal waveform for fixed dot quantity
printing, and FIG. 11 shows an example of fixed dot quantity
printing printed using this common drive signal waveform. Each
square of the matrix corresponds to the area of one pixel. In the
example shown in FIG. 11, the fixed quantity dot is printed on
every other pixel in the main scanning direction.
FIG. 12 is a common drive signal waveform for variable dot quantity
printing, and FIG. 13 is an example of variable dot quantity
printing printed using this common drive signal waveform. As shown
in FIG. 12, for each pixel period the common drive signal waveform
for variable dot quantity printing is divided into a small dot
period and a medium dot period. A small dot pulse W1 is produced in
the small dot period and a medium dot pulse W2 is produced in the
medium dot period. When printing small dots, only small dot pulses
W1 are applied to the piezoelectric element, and when printing
medium dots, only medium dot pulses W2 are applied to the
piezoelectric element. Applying both W1 and W2 pulses to the
piezoelectric element results in the printing of large dots (see
FIG. 13).
The drive voltage V1 of the common drive signal waveform for fixed
dot quantity printing shown in FIG. 10 is determined based on the
first drive voltage information VH1. Similarly, the drive voltages
V2 and V3 of the common drive signal waveform for variable dot
quantity printing shown in FIG. 12 are determined based on the
second and third drive voltage information VH2 and VH3. FIG. 9(b)
shows the relationship between the drive voltage information
symbols VH1-VH3 and the voltage values. In the example of FIG.
9(a), a symbol S is assigned to the first drive voltage information
VH1, so the drive voltage V1 of FIG. 10 is set at 24 volts (how the
voltage is set is explained later).
The values of the width L1 of the waveform high voltage level shown
in FIGS. 10 and 12 and of the width L2 of the waveform zero level
shown in FIG. 12 are determined in accordance with the actuator
rank information AR. FIG. 9(c) shows that a rank of the actuator
(that is, the actuator circuit 90 and piezoelectric element) is
specified by the actuator rank information AR. The actuator rank is
set beforehand by checking the actual characteristics of the
actuator (actuator circuit 90 and piezoelectric element). A
detailed explanation of the relationship between actuator rank and
waveform width L1 and L2 is omitted.
The ink emission amount information IW1 and IW2 of FIG. 9(d) shows
the weight ratio (the proportion taking the average as 100%)
between the amounts of ink (for fixed dot quantity) emitted by the
second and third actuator chips 92 and 93 (that is, the actuator
chips used for color printing). Variations arising during the
manufacturing process result in slight variations in ink emission
amount from actuator to actuator. In order to effect good quality
printing, is it desirable to be able to control accurately the ink
amounts emitted by each actuator. In this embodiment, information
about the ink emission amount of each of the actuators used for
color printing is supplied to the print driver (not shown) in the
computer 88, and the actuator-based variations in ink emission
amount are taken into account in the image processing that takes
place in the printer driver. Specifically, when relatively small
amounts of ink are emitted, the dot printing density (the number of
dots printed in a fixed area) is increased. Conversely, when
relatively large amounts of ink are emitted, the dot printing
density is decreased. Ink emission amount information may be set
with respect to all of the actuators on the print head unit 60.
The printing mode information RM of FIG. 9(e) is information
specifying the preferable printing mode to be applied to the print
head unit 60. Dot printing mode information, including dot printing
mode parameters, is stored in the PROM 43 shown in FIG. 3.
FIGS. 14(A) and 14(B) show the parameters that define a dot
printing mode. FIG. 14(A) is an example of sub-scanning feeds using
four nozzles, and FIG. 14(B) shows the parameters for that dot
printing mode. In FIG. 14(A) the solid circles containing numbers
show the positions of the four nozzles after the nozzles have been
fed in the sub-scanning direction. The circled numbers 0--3 are the
numbers of the nozzles. The positions of the nozzles are moved in
the sub-scanning direction after completion of each main scanning
pass. This movement of the nozzles in the sub-scanning direction is
a relative movement that is actually realized by using the feed
motor 22 to move the paper.
As shown at the left in FIG. 14(A), in this example the
sub-scanning feed amount L is a fixed value of two dots. That means
that each time sub-scanning feed is effected, the four nozzles are
each moved in the sub-scanning direction by the amount of two dots.
FIG. 14(B) shows the parameters relating to this dot printing mode.
These parameters include nozzle pitch k, in dots, the number of
working nozzles N, the number of scan repeats s, the number of
effective nozzles Neff, and the sub-scanning feed amount L, in
dots.
In the example of FIGS. 14(A) and 14(B), the nozzle pitch k is 3
dots and the number of working nozzles N is 4. The number of
working nozzles means, out of the total number of nozzles, the
number that is actually used. The number of scan repeats s means
that dots are formed at every s dot positions in one main scanning
pass. Therefore, the number of scan repeats s is equal to the
number of nozzles used to form all of the dots along each raster
line. In the example of FIG. 14, the number of scan repeats s is 2.
A dot printing mode having the scan repeats s of two or more is
called "overlap printing."
The number of effective nozzles Neff is given by dividing the
number of working nozzles N by the number of scan repeats s. The
number Neff can be thought of as indicating the net number of
raster lines that can be printed with one main scanning pass.
The table of FIG. 14(B) lists the sub-scanning feed amount L,
cumulative feed amount .SIGMA.L and offset F for each sub-scanning
feed. Assuming that the periodical positions of the nozzles
(located every four dots, in the case of FIG. 14(A)) prior to their
first sub-scan feed are reference positions of offset zero, offset
F indicates how many dot positions the nozzles are away from the
reference positions in the sub-scanning direction after the
sub-scanning feed. As shown in FIG. 14(A), for example, the first
sub-scanning feed moves the nozzles in the sub-scanning direction
by a sub-scanning feed amount L (two dots). The nozzle pitch k is
three dots, so after the first sub-scanning feed the nozzle offset
F is 2. After the second sub-scanning feed the nozzles have been
moved .SIGMA.L=4 dots from their initial positions, and the offset
F is 1. After the third sub-scanning feed the nozzles have been
moved .SIGMA.L=6 dots from their initial positions and the offset F
is zero. The third sub-scanning feed returns the nozzle offset F to
zero, so with three sub-scanning passes comprising one sub-cycle,
the dots of all the raster lines in the printable area can be
formed by repeating this sub-cycle.
FIGS. 15(A)-15(D) show the scanning parameters of four dot printing
modes that have substantially the same printing speed. In the case
of the first dot printing mode, in FIG. 15(A), the nozzle pitch k
is 6 dots, the number of working nozzles N is 48, the number of
scan repeats s is 2 and the number of effective nozzles Neff is 24.
Six different values of 20, 27, 22, 28, 21, and 26 are used as the
sub-scanning feed amounts L [dots]. The parameters of the second
dot printing mode of FIG. 15(B) are the same as those of the first
mode, except for the sub-scanning feed amounts L.
The parameters of the third dot printing mode, in FIG. 15(C), are
as follows. The nozzle pitch k is 6 dots, the number of working
nozzles N is 47, the number of scan repeats s is 2 and the number
of effective nozzles Neff is 23.5. Two values of 21 and 26 are used
as the sub-scanning feed amounts L. The parameters of the fourth
dot printing mode of FIG. 15(D) are the same as those of the third
mode, except for the sub-scanning feed amounts L.
The number of working nozzles N in the case of each of the first
two modes is not the same as the number of working nozzles N used
in each of the third and fourth modes, the number being 48 in the
first two modes and 47 in the third and fourth modes. However, the
numerical difference is less than about 10%, so the printing speeds
are virtually the same. The parameters for such a plurality of dot
printing modes having substantially the same printing resolutions
and the same printing speeds, can be registered beforehand in the
printer PROM 43 as a plurality of selectable dot printing mode
information.
In the case of the example shown in FIG. 9(e), the printing mode
information RM specifies one mode as a high quality printing mode
and another as a high speed printing mode. In the high quality mode
high quality images are printed at a relatively slow speed, while
in the high speed mode, the image quality is lower but the images
can be printed at a higher speed. For the high quality printing
mode, there has been prepared a plurality of dot printing modes for
printing at the same resolution at speeds that are substantially
the same, and, similarly, for the high speed printing mode there
has also been prepared a plurality of dot printing modes for
printing at the same resolution at speeds that are, again,
substantially the same. "Printing at substantially the same speeds"
means a printing speed differential of up to about 10%.
When a plurality of dot printing modes are available at the same
resolution and at substantially the same speed, the quality of the
images printed in each dot printing mode depends on the alignment
characteristics of the nozzles (that is, the actual positions of
each nozzle) in the print head unit 60. For example, even if the
four dot printing modes shown in FIGS. 15(A)-15(D) are available as
high quality printing modes, there are cases in which a higher
quality can be obtained in one of the modes than in the others.
Accordingly, by determining the preferable dot printing mode that
attains a better print image quality, in accordance with the nozzle
alignment characteristics, and displaying this on the print head
unit 60 as printing mode information RM, it is possible to produce
good quality printing by using a preferred dot printing mode for
the printer 20.
FIG. 16 is a flow chart of the steps of installing the print head
unit 60 on the printer 20. In step S1 the print head unit 60 is
mounted on the printer 20, and in step S2 the head identification
information is input. When a head ID seal 100 is adhered to the
print head unit 60, as shown in FIG. 4, there are a number of ways
the head identification information can be input. As a first
method, an operator can key in the head identification information
via the keyboard (not shown) of the computer 300. In the case of
this method, the mode selection information writing module 310
(FIG. 1) writes the head identification information into the PROM
43. A second method comprises using a barcode reader to read the
barcode 102. As shown in FIG. 2, the printer 20 is provided with a
barcode reader 110 for optically reading the head ID seal 100. The
barcode reader 110 can read the barcode 102 on the head ID seal 100
automatically when the print head unit 60 is moved in the main
scanning direction. The printer 20 does not have to be equipped
with a barcode reader 110; instead, a separate barcode reader may
be used. Also, instead of a barcode, other types of codes can be
used that can be read physically (i.e., optically, magnetically or
electrically) and mechanically.
The head identification information thus input is stored in the
PROM 43. Also, the first and second ink emission amount information
IW1 and IW2 and the printing mode information RM are registered in
the printer driver 306. The PROM 43 is provided on a printed
circuit board in the printer 20 and therefore remains in the
printer, irrespective of the presence or absence of the print head
unit 60. As such, when a print head unit 60 is replaced, the head
identification information registered in the PROM 43 is replaced by
the head identification information of the new print head unit
60.
In step S3, the ink cartridges are installed in the print head unit
60, charging the print head 28 with ink. In step S4, ink is emitted
by the nozzle array to print a prescribed test pattern. This
pattern reflects the characteristics of the print head unit 60
being used. More specifically, the drive signal waveform (FIG. 10
or 12) generated by the head drive circuit 52 is adjusted on the
basis of the drive voltage information VH1-VH3 and the actuator
rank information AR. To ensure that the tone levels of the image
data are reproduced properly, dot printing densities for each ink
are determined by the printer driver based on the ink emission
amount information IW1 and IW2. The dot printing mode that is
actually used is determined by the printing mode information RM,
and the processing of the image data in the printer driver, and the
main and sub-scanning in the printer 20, are controlled to ensure
that printing proceeds in accordance with the dot printing mode
thus set.
Some of the parameters including the drive signal waveform
parameters V1-V3 and L1-L2, the ink emission amounts and the
preferable dot printing mode have.an affect on the printing
outcome, and so are referred to as "printing process parameters."
As can be understood from this explanation, the control circuit 40
and printer driver 306 function as a control section implementing
printing processing in accordance with the printing process
parameters specified by the head identification information. These
functions of the control section can be divided between the control
circuitry in the printer 20 and the computer 300 connected to the
printer 20. Depending on the printing process parameters concerned,
it may also be possible for the functions of the control section to
be implemented entirely within the printer 20 or entirely within
the computer 300.
In step S5, the test pattern is examined by an inspector. If the
test pattern does not meet a prescribed standard, the head is
cleaned and steps S3 and S4 are repeated. If the head cleaning
operation has been run a prescribed number of times but the test
pattern still does not meet the required standard, in step S7 the
print head unit 60 is replaced and steps S2 to S5 are repeated. The
new print head unit 60 also has a head ID seal 100, making it easy
to set proper printing process parameters for that print head unit.
After passing the printing quality inspection, the print head 28 is
filled with fluid for shipping of the printer 20, completing the
installation of the print head unit 60.
In the first embodiment described in the foregoing, head
identification information is assigned to each print head unit 60
corresponding to the variations in the characteristics of the print
head unit 60 arising in the course of the manufacturing process,
with the head identification information being displayed in a
readable form. This makes it easy for the various printing process
parameters, such as drive signal waveform and dot printing mode,
for example, to be set in accordance with the head characteristics
of the print head unit 60 installed in the printer. In particular,
dot printing mode information that includes plural sets of dot
printing mode parameters are stored beforehand in a PROM 43 on a
circuit board in the printer 20, and the printing mode information
RM displayed on the print head unit 60 facilitates the setting of
the preferable dot printing mode that best suits the
characteristics of the print head unit 60. This is particularly
advantageous when a user replaces the print head unit 60, since it
allows good quality printing to be attained with the new print head
unit simply by setting the head identification information in the
printer driver and the PROM 43.
C. Second Embodiment
FIG. 17 is a diagram of the print head 28a of a print head unit
according to a second embodiment of the invention. The print head
28a has a programmable ROM (PROM) 200 in which is stored the head
identification information of FIGS. 9(a)-9(e). The PROM 200 is
provided on the print head unit and is therefore replaced when the
print head unit itself is replaced. The head identification
information stored in the PROM 200 is read out for use by the
control circuit 40 in the printer 20 and the printer driver 306 in
the computer 300.
Some types of printers may be equipped with multiple print head
units. FIG. 18 shows an example of the relationship between the
print head units and the control circuit in a printer equipped with
multiple print head units. The example shown in FIG. 18 has a first
print head unit 60a for monochrome printing and a second print head
unit 60b for color printing. Each of the print head units 60a and
60b can be installed and removed independently. The print head
units 60a and 60b are provided with a PROM 200a and a PROM 200b for
storing the print head identification information of each print
head unit. Control circuit 40a has head drive circuits 52a and 52b
for supplying respective drive signals to the print head units 60a
and 60b. Instead of using the PROMs 200a and 200b, the type of head
ID seal shown in FIG. 9(a) can be adhered to each print head
unit.
With such a configuration where a single printer can be equipped
with multiple print head units, if head identification information
is set for each print head unit, even if any of the print head
units is replaced, it is still possible to achieve good quality
printing based on the characteristics of the print head unit
concerned.
A configuration that can be equipped with multiple print head units
can still be arranged so that a common drive signal is supplied to
the multiple print head units from a single drive circuit. With
such an arrangement, as in the first embodiment, some of the
printing process parameters that do not affect the drive signal
waveform (a preferable dot printing mode and dot printing density
corresponding to ink emission amount) can be determined according
to the characteristics of each print head unit. However, an
arrangement such as that of FIG. 18 in which a plurality of head
drive circuits is provided corresponding to the plurality of print
head units is advantageous in that drive signals each having a
preferred waveform for a particular print head unit can be supplied
to the print head unit concerned.
When there is provided a PROM 200 for each print head unit, an
arrangement can be used whereby the control circuit 40 (FIG. 3) can
also be used to write the service history of each print head unit
to the PROM 200. For example, a counter could be provided in the
control circuit 40 to count the number of ink emissions from a
print head unit, and the count value may be stored in the PROM. 200
of the print head unit. With such an arrangement, even if a print
he-ad unit is removed in mid-service, the number of times the print
head unit had been used could be retrieved from the PROM 200,
making it possible to judge the working life of the print head
unit. Other service history items that can be used include the
number of ink emissions for each actuator or for each ink.
D. Third Embodiment
FIG. 19 is a function block diagram of a configuration used to
effect drive control for each dot printing mode, in accordance with
a third embodiment of the invention. The block diagram shows a mode
ID memory 202, printing mode setting section 204, printing mode
table 206, drive control section 208, main scanning drive section
210, sub-scanniing drive section 212, print head drive section 214,
raster data storage section 216, print head 28 and paper P.
A plurality of dot printing mode information is stored in the
printing mode table 206. The printing mode table 206 shows the
printing resolution, mode group, mode ID, the number of working
nozzles N and the sub-scanning feed amount L. There are more
parameters, which are not shown in FIG. 19.
In the FIG. 19 configuration, the plurality of dot printing modes
stored in the printing mode table 206 are divided into four mode
groups M1-M4, by combination of printing resolution and printing
speed. The first mode group M1 is a "fast at 360 dpi" group; the
second mode group M2 is a "fine (and slow) at 360 dpi" group; the
third mode group M3 is a "fast at 720 dpi" group, and the fourth
mode group M4 is a "fine (and slow) at 720 dpi" group. The contents
of the printing mode table 206 are described in further detail
later.
The mode ID memory 202 contains the mode IDs (mode selection
information) specifying the preferable dot printing mode for each
mode group. Based on printing data received from the computer 300
and a mode ID received from the mode ID memory 202, the printing
mode setting section 204 supplies to the drive control section 208
and raster data storage section 216 parameters defining the main
and sub-scanning operations. The printing data is the same as the
final color image data FNL of FIG. 1. The header of the printing
data (not shown) includes data selecting one of the mode groups M1
to M4. The printing mode setting section 204 uses this mode group
and the mode ID supplied from the mode ID memory 202 to determine
the dot printing mode to be used in the printing.
Scanning parameters for the dot printing mode thus determined,
including the number of working nozzles N and the amount L of
sub-scanning feed, are sent to the drive control section 208 and
the raster data storage section 216 by the printing mode setting
section 204. Because the number of working nozzles N and the
sub-scanning feed amount L may change each scanning pass, the
scanning parameters including these data are sent to sections 208
and 216 prior to each scanning pass.
The raster data storage section 216 stores the printing data in a
buffer memory (not shown) according to the scanning parameters
including the number of working nozzles N and the sub-scanning feed
amount L. The drive control section 208 controls the main scanning
drive section 210, sub-scanning drive section 212 and print head
drive section 214 in accordance with the scanning parameters
including the number of working nozzles N and the sub-scanning feed
amount L.
The mode ID memory 202 and printing mode table 206 are provided in
the PROM 43 shown in FIG. 3. The functions of the printing mode
setting section 204, drive control section 208 and raster data
storage section 216 are manifested by means of the CPU 41, RAM 44
and head drive circuit 52 of the control circuit 40 of FIG. 2. The
main scanning drive section 210 is constituted by the feed travel
mechanism of the carriage 30 with carriage motor 24, shown in FIG.
2, while the sub-scanning drive section 212 is constituted by a
paper feed mechanism that includes the feed motor 22. The print
head drive section 214 is constituted by the head drive circuit 52
of FIG. 3 and the actuator circuit 90 of FIG. 7.
FIG. 20 shows scanning parameters for three dot printing modes at
substantially the same printing speed. The three dot printing modes
are ones included in the fourth mode group M4. With respect to
parameters, in the first dot printing mode, in FIG. 20(A), the
nozzle pitch k is 6 dots, the number of working nozzles N is 48,
the number of scan repeats s is 2 and the number of effective
nozzles Neff is 24. Six different values of 20, 27, 22, 28, 21, and
26 are used as the sub-scanning feed amounts L [dots]. The
parameters of the second dot printing mode of FIG. 20(B) are the
same as those of the first mode, except for the sub-scanning feed
amounts L. With respect to the parameters of the third dot printing
mode, in FIG. 20(C), the nozzle pitch k is 6 dots, the number of
working nozzles N is 47, the number of scan repeats s is 2 and the
number of effective nozzles Neff is 23.5. Two values of: 21 and 26
are used as the sub-scanning feed amounts L [dots].
While the first two modes use 48 working nozzles compared to 47 in
the third mode, the difference in the number of working nozzles is
less than about 10% across the three modes. Since the printing
speed is substantially proportional to the number of effective
nozzles Neff (=N/s), the printing speeds of the three modes of FIG.
20 can be regarded as substantially the same. Here, "printing at
substantially the same speeds" means a printing speed difference of
up to about 10%.
FIGS. 21(A) and 21(B) show the contents of the printing mode table
206 and mode ID memory 202. The multiple dot printing modes
contained in the printing mode table 206 are divided into the four
mode groups M1-M4. Mode groups M1 and M3 each contains one printing
mode, group M2 contains two printing modes, and group M4 contains
three printing modes. Within one mode group, printing speeds (that
is, the number of effective nozzles N/s) are substantially the
same. For example, the number of effective nozzles Nd1/s, Nd2/s,
Nd3/s of the three modes in the mode group M4 are substantially the
same. In the examples of FIGS. 20(A)-20(C), Nd1/s =Nd2/s=24,
Nd3/s=23.5.
The "fine" mode groups M2 and M4 are comprised of overlapping type
dot printing modes with the number of scan repeats s of 2. In the
case of the "fast" mode groups M1 and M3 the number of scan repeats
s is 1. The number of scan repeats s may take a value. including a
fraction. A dot printing mode in which the number of scans is
larger than 1 and smaller than 2 is termed a "partial overlap
system." A partial overlap dot printing monde can be used in the
"fast" mode groups M1 and M3. Assuming, for example, that the
number of working nozzles N is 48 and the sub-scanning feed amount
is set at a constant 41 dots, the result would be a partial overlap
mode with the number of effective nozzles Neff of 41 and the number
of scan repeats s of about 1.17 (i.e., 48/41). In the case also of
a partial overlap mode, sub-scanning feed amount L can be comprised
of a plurality of different values.
While each mode group is constituted of the dot printing modes
having the same resolution and substantially the same speed, the
image quality of the print depends on the alignment characteristics
of the nozzles in the print head 28 (that is, the actual positions
of the nozzles). Thus, in some cases one of the dot printing modes
of the mode group M4 may produce a higher quality than the other
two modes. Therefore, if a preferable printing mode is determined
for each mode group to provide a higher image quality in accordance
with the nozzle alignment characteristics and the preferred mode ID
is registered in the mode ID memory 202, it is possible to attain
better quality printing by utilizing the preferable dot printing
mode for the printer 20.
As can be readily understood from FIG. 21(A), in accordance with
the third embodiment, for each printing resolution, the larger
number of dot printing modes are prepared as the printing speed
decreases. Normally, at relatively slow printing speeds there tends
to be a larger image quality difference between dot printing modes.
In this embodiment, when the printing speed is relatively low, a
preferable dot print mode can be selected from a larger number of
modes having the same printing resolution, and it is therefore
easier to improve the image quality. Conversely, at higher printing
speeds the quality difference between modes is not so large, so it
is sufficient to prepare a smaller number of printing modes.
Although in the example of FIG. 21(A) the "fast" mode groups M1 and
M3 are each comprised of one printing mode, they may instead each
be comprised of multiple printing modes.
The mode ID memory 202 stores four mode IDs for selection a
preferable dot printing mode in each of the four mode groups M1-M4.
A preferable dot printing mode can be set independently for each of
the mode groups. For each printer, this facilitates the setting of
a preferable dot printing mode for each mode group (that is, for
each combination of printing resolution and speed). This effect is
particularly noticeable when each mode group contains a
multiplicity of printing modes.
In the third embodiment described above, the number of available
dot printing modes increases as the printing speed decreases, with
respect to each resolution of 360 dpi and 720 dpi. However, in the
present invention, it is sufficient to prepare the larger number of
available dot printing modes as the printing speed decreases with
respect to at least one printing resolution, and other mode groups
having other printing resolutions may include an identical number
of dot printing modes from each other.
E. Variations
E1. First Variation
The PROM 43 in the control circuit 40 of the printer 20 (FIG. 2)
and the PROM 200 (FIG. 16) mounted on the print head unit may be
constituted by non-volatile memory instead of programmable ROM.
E2. Second Variation
The head identification information items depicted with reference
to each of the above embodiments are only examples. Various other
head identification information items determined beforehand in
relation to print head unit characteristics that are subject to
variations in the manufacturing process may be assigned to the
print head unit.
E3. Third Variation
The information items included in the head identification
information may be aimed at various targets. For example, when a
print head unit is provided with a plurality of actuators, the head
identification information may be arranged to include information
for setting multiple sets of printing process parameters for the
actuators. Also, the head identification information may include
information for setting multiple sets of printing process
parameters for multiple sets of nozzle arrays. Moreover, the head
identification information may include information for setting
multiple sets of printing process parameters for multiple sets of
nozzle rows. This would enable the setting of printing process
parameters adapted for each such target, resulting in high quality
printing.
E4. Fourth Embodiment
In the above embodiments the dot printing modes have been described
with reference to one color. Color printing with a plurality of ink
can be implemented by applying the above dot printing mode to a
plurality of colors.
E5. Fifth Embodiment
This invention is also applicable to monochrome printing. It is
also applicable to printing in which multiple tones are reproduced
by using a plurality of dots to reproduce one pixel. It is also
applicable to drum-scanning printers, in which case the main
scanning direction would be the direction of drum rotation and the
sub-scanning direction would be the direction of carriage travel.
The invention is. applicable not only to inkjet printers but to all
dot printing apparatuses that use a print head having an array of
multiple dot formation elements to print on a printing medium.
Here, "dot formation elements" refers to elements used to form dots
such as the ink nozzles of an inkjet printer.
E6. Sixth Embodiment
While the configurations of the above embodiments have been
described in terms of hardware, the configurations may be partially
replaced by software. Conversely, software-based configurations may
be partially replaced by hardware. For example, some of the
functions of the control circuit 40 (FIG. 2) may be implemented by
the computer 300. In such a case, a computer program such as the
printer driver 306 or the like would effect the same functions as
the control functions of the control circuit 40.
Computer programs for realizing such functions may be provided
stored on a storage medium that can be read by computer such as
floppy disks and CD-ROM disks. The computer system 300 can transfer
the program from the storage medium to an internal or external
storage device. Alternatively, the programs may be supplied to the
computer system 300 by a program provider apparatus via a
communication path. The computer program functions are realized by
the stored program being executed by the microprocessor of the
computer 300. The computer program on the storage media may also be
executed directly by the computer system 300.
The computer system 300 as referred to herein is taken to include
hardware and operating system, with the hardware functioning under
the control of the operating system. Some of the above functions
may be implemented by the operating system instead of by an
application program.
The computer readable storage media are not limited to portable
storage media such as floppy disks and CD-ROM disks, but also
include internal storage and memory devices such as various types
of RAM and ROM as well as external fixed storage such as hard
disks.
Industrial Applicability
This invention can be applied to inkjet printers, inkjet facsimile
machines, inkjet copy machines and various other type of
apparatuses in which a print head is used in printing.
* * * * *